This study presents the first documented observations of a brachyuran crab's proactive fishing behaviour in conjunction with mangrove pneumatophores which are employed as prey-localization devices. All ecological data were recorded in situ using simple behavioural observations, visual census and field experiments. Field experiments were based on stimulus-response and ecological surveys on random displacement. Assemblages of Metopograpsus messor were observed daily performing a foraging/predatory tide-related cyclic behaviour pattern in an arid mangrove ecosystem which experiences challenging environmental conditions. Prey-localizing behaviour was observed during the flood tide when pneumatophore-borne vibrations were used to identify potential prey. The prey simulation field experiment (where a single pneumatophore was stimulated by knocking) showed that in >93% of instances a crab approached the exact pneumatophore being stimulated. As water levels increased during the tidal cycle M. messor was observed climbing pneumatophores. The crabs anchored themselves to the pneumatophore just above the water level with their pereiopods. The chelipeds were positioned in a pincher-like trap, and remained in a ‘capture-position’ waiting for prey to move within striking range. This characteristic fishing behaviour was performed daily by a population of M. messor. Ecological observations suggest that both these predatory behaviours are associated with the fish Aphanius dispar dispar in a direct prey–predator relation. Evidence suggests that these fishing behaviours evolved due to characteristics within the M. messor phylogeny (foraging in intertidal zones; daily displacement following tidal levels; high sensitivity to vibrations; and an opportunist diet) and its associated environment (presence of pneumatophores and high availability of a fish resource).

After the recent detection, by both morphology and DNA barcodes, of the larval stages of an unknown species of pea crab (Pinnotheres sp.) in European waters, adults of this crab are herein reported and described as a new species. The current known geographic distribution of the species comprises the Gulf of Cádiz in the eastern Atlantic and the adjacent Mediterranean waters of the south of the Iberian Peninsula (Alboran Sea), where this crab is well-established inside the anomiid bivalve Anomia ephippium. In the Gulf of Cádiz, the species displayed a relatively high prevalence: on average, 55.6–77.7%, in A. ephippium samples. The dominant demographic categories of the new species were soft females (61.8–77.0%) with fewer males (17.7–21.10%). Most of the host bivalves carried only one crab; in bivalves harbouring two crabs, heterosexual pairs were collected more frequently than expected by chance, which suggests that they could be mated pairs. A strong correlation between host size and soft female size was found (r = 0.73, P < 0.01) indicating that space availability within hosts seems to be relevant in determining the size of the sedentary phase of the new crab species.

The brush-clawed shore crab Hemigrapsus takanoi is a native species from the Western Pacific and an invader of the European Atlantic coast from northern Spain to southern Denmark. Despite the increasing concern about its rapid expansion, little is known about the early stages in its life history. In the present study, the larval morphology of H. takanoi is described and illustrated from specimens obtained in the laboratory from its type locality, Tokyo Bay, Japan. Its larval development follows the pattern of Varunidae, that involves five zoeae and one megalopa. The morphological characters of the larvae of H. takanoi are compared with those of the other known Hemigrapsus species of the North Pacific. In addition, to facilitate an early detection of the invasive species of Varunidae inhabiting European Atlantic waters, a summary of the key characters to identify their larval stages is included.

The present study investigated the population dynamics of Hepatus pudibundus in the Cananéia region, in southern São Paulo state, Brazil, focusing on population structure, growth parameters, longevity, sex ratio, reproduction and recruitment juvenile period. Sampling was performed monthly at seven stations from July 2012 to June 2014, using a shrimp fishing boat. A total of 1650 specimens were collected: 551 males and 1099 females. The males were larger than females. Reproductive females were captured throughout the study period and juveniles were captured in most months. Both of these demographic categories were positively correlated with temperature. Growth parameters showed differences between sexes: CW∞ = 78.91 mm, k = 0.0066 day−1, t0 = 0.0965 for males and CW∞ = 69.71 mm, k = 0.0053 day−1, t0 = −0.2404 for females. Longevity was estimated at 1.91 and 2.40 years for males and females, respectively. The findings provide a greater understanding of the life cycle in this species. Additionally, since trawl nets are not selective, this study also provides information for better trawl fishery management, addressing not only the target shrimp but also the by-catch species.

Four multidisciplinary oceanographic surveys were conducted in November and December from 2007 to 2010, along the Mauritanian coast (NW Africa). A total of 10,514 brachyuran crabs belonging to 33 species were captured in 316 hauls at depths between 79 and 1867 m. The most specious family was Inachidae represented by nine species; the remaining 24 species belonged to 16 other brachyuran families. Monodaeus cristulatus is reported for the first time since its original description. Seven other species, Ethusa rugulosa, Pseudomyra mbizi, Inachus grallator, Macropodia gilsoni, Macropodia hesperiae, Solenolambrus noordendei and Spinolambrus notialis extend their range of distribution northwards and, together with Goneplax barnardi, are reported here for the first time in Mauritanian waters. New data about depth ranges are reported for Acanthocarpus brevispinis, Ethusa rugulosa, Inachus aguiarii, Inachus grallator, Inachus nanus, Macropodia macrocheles, Solenolambrus noordendei, Spinolambrus notialis, Liocarcinus corrugatus and Monodaeus cristulatus. New data relating to the spawning period for most of the species are also included, as are some biogeographic and bathymetric considerations about brachyurans studied in the area.

The swimming crab Achelous spinimanus is an important fishery component of several countries in the Western Atlantic; therefore, knowledge of the different phases of its life cycle is essential for good management of this resource. The juvenile development of A. spinimanus was investigated in the laboratory, from megalopae captured in neuston samples at Ubatuba, São Paulo, Brazil (23°26′S 46°09′W), during the summer months of 2005–2007. Rearing was performed in a constant temperature (25 ± 1°C), filtered seawater from the collection location (35 psu) and natural photoperiod. We obtained nine stages of the juvenile phase. All the morphological characters that allow the recognition of the first juvenile stage were drawn and described, as well as the main alterations that occur in the following stages. The sexual differentiation based on the number of pleopods becomes apparent from the third stage on. Some important characters in the identification of the species at the juvenile phase are the number of segments on the exopod of antennule, on the antennal flagellum and on the palp of mandible, beyond the absence of pleopods (even rudimentary) in the first stage.

Although Parthenopidae is a brachyuran decapod family comprising almost 140 species, there is little knowledge about its larval morphology. There are only two complete larval developments reared in the laboratory and some larval stages described for seven species. In the present work these data are compared and analysed. A summary is made of the larval features that characterize parthenopids that can be used to distinguish them from other brachyuran larvae. In addition, the megalopa stage of Derilambrus angulifrons and Parthenopoides massena was collected from plankton and identified by DNA barcodes. The morphology of the megalopa of D. angulifrons is described for the first time, and that of P. massena is compared with a previous description.

Selwynia, is regarded as a senior subjective synonym of Aphanodactylus (Crustacea: Brachyura: Pinnotheroidea: Aphanodactylidae). This synonymy does not affect the family name Aphanodactylidae. A diagnosis is provided for Selwynia laevis and this species is re-described.

The porcellanid crab Porcellana sayana is, for the first time, reported to have a symbiotic association with the crab Stratiolibinia bellicosa. This is also the first record on the association between the porcelain crab P. sayana and a brachyuran crab on the Brazilian coastline. In addition, this is the second record of association of P. sayana with a Majoidea crab.

Three brachyuran species of the family Xanthidae, Atergatis ocyroe, Macromedaeus voeltzkowi and Macromedaeus quinquedentatus are recorded from the Iranian coast of the Gulf of Oman. These specimens were collected in 2009 and 2010 from the Iranian waters of the Gulf of Oman. Among these species, A. ocyroe is a new record for the Gulf of Oman and M. quinquedentatus is a new record for the Iranian coast. This is the second record of M. voeltzkowi from the Iranian coast, whereas there is still no record from the Arabian coast of the Gulf of Oman. The diagnostic characteristics of the species and some taxonomic remarks are reported upon in this paper.

Thirty-eight specimens collected along the intertidal zone from the southern Pacific of Mexico were examined, resulting in the extension of the distribution ranges for Eucinetops lucasii Stimpson, 1860 from Mazatlán, Sinaloa to San Agustín Bay, Oaxaca (approximately 1488 km southward), E. rubellulus Rathbun, 1923 from Maruata, Michoacán to La Tijera Beach, Oaxaca (802 km southward), and Uca musica Rathbun, 1914 from San Blas, Nayarit to La Encrucijada Biosphere Reserve, Chiapas (1763 km southward).

The reproductive cycle of Cardisoma guanhumi was described from the analysis of seasonal variation of the gonadal maturation stages. The first maturity for both sexes was determined based on three different tests: inflexion point on the curve; relevant character (morphometry); and histological analysis (physiology). In addition, some aspects of sexual dimorphism for the population were studied. A total of 353 individuals caught in north-eastern Brazil between December 2006 and November 2007 were analysed. The sex-ratio was statistically equal (P ≥ 0.05) and the carapace width (CW) of the females ranged from 4.34 to 8.56 cm and of the males from 2.84 to 9.22 cm. Mature females with fully developed gonads begin to appear in the dry season (August) and ovigerous females occurred from November to February, suggesting that spawning occurs mainly during the rainy season. The CW of first sexual maturity for females ranged from 5.87 cm to 6.70 cm and males from 6.22 cm to 7.20 cm. The highest percentage of individuals caught were juveniles, indicating the need for a targeted effort to preserve the species.

The population biology of Epialtus bituberculatus was compared between two different intertidal localities with differing levels of wave exposure. Sampling was conducted monthly between January and December, 2001 on seaweed banks of Sargassum cymosum in the intertidal zone of the rocky shores Grande (GR) (23°23′S–45°03′W) and Domingas Dias (DD) (23°29′S–45°08′W). Four hundred and twenty-eight crabs were captured at the GR site: 111 juvenile males, 106 adult males, 57 juvenile females, 17 adult females and 137 ovigerous females; while 455 specimens were obtained at the DD site: 76 juvenile males, 113 adult males, 37 juvenile females, 40 adult females and 189 ovigerous females. The population from GR showed a non-normal distribution and from DD a normal distribution. The sex-ratio (female/male) was 1:0.97 at GR (χ2 = 0.77, P = 0.084), whereas it was 1:1.41 at DD (χ2 = 13.03, P < 0.001). The largest individuals occurred at DD (U = 78249.0, P < 0.001). The estimated size at sexual maturity was 6.3 and 5.0 mm carapace width (CW) for males, and 5.4 and 5.2 mm CW for females, from GR and DD, respectively. The observed differences in E. bituberculatus between the studied localities might be explained by the different degrees of wave exposure between sites. However, other factors that might also explain the observed differences (e.g. temperature, salinity and food availability) cannot be discarded as relevant in influencing the population structure between sites herein studied.

The present contribution reports on a small collection of leucosiid crabs from Qatar. Four species are reported upon, three of which are new additions to the brachyuran fauna of the Persian Gulf, and one, the first record for the species from Qatar.

Two rare species of xanthid crab (Brachyura: Xanthidae) are reported for the first time in the territorial waters of Pakistan. Odhnea echinus and Paraxanthodes cumatodes were collected from Sonmiani Bay, on the coast of Pakistan. These species are known from only a few specimens and localities globally. The male gonopods are figured for the first time for these two species, and updates on their taxonomy are also provided.

This investigation aimed to study the relative growth, morphological sexual maturity and fecundity of the swimming crab Achelous spinicarpus in a tropical region, on the south-eastern continental shelf of Brazil (25°S). Biometry of all specimens was conducted, including measurements of the cephalothorax, cheliped, abdomen and gonopods. Relative growth was described based on the equation for allometry (y = axb), and size at sexual maturity was determined from inflections in relations involving the cheliped, gonopods (males), and abdomen (females), as dependent variables, related to the cephalothorax width (independent variable). Fecundity was estimated by the gravimetric method. The relations of the length of the chelar propodus and carpal spine to the carapace width without the lateral spines (CW) showed positive allometry in both sexes, with a significant variation in the constant ‘b’ for males between the developmental stages (juvenile and adult) and the size at maturity estimated at 37 mm CW. In females, the abdomen was most appropriate for the estimate of morphological maturity, which occurred at a smaller size (32 mm CW), with a change in the growth pattern between the stages, passing from isometric (juveniles) to positive allometric (adults). The gonopods also showed different growth rates between developmental stages, in synchrony with the variables of the cheliped. Mean fecundity for the species was 53,984 eggs, with a positive correlation between the number of eggs exteriorized and the size of the female; the equations allowed interconversion between these variables, due to the adjustment of the power function (r2 ≥ 86%).

A total of 16 species of intertidal brachyuran crabs were recorded from the three major estuaries (Punta Banda, False Bay-San Quintín and Laguna Manuela) of the west coast of the state of Baja California, Mexico. The species belong to 7 families: Cancridae (3), Grapsidae (2), Ocypodidae (2), Panopeidae (3), Pinnotheridae (4), Portunidae (1) and Varunidae (1). New distributional records include an extension of the northern limits of Cyrtoplax schmitti Rathbun, 1935, Panopeus purpureus Lockington, 1877, Goniopsis pulchra (Lockington, 1877), Uca princeps (Smith, 1870) and Pinnixa longipes (Lockington 1877).

This paper aims to study the morphological and gonadal maturity of the swimming crab Callinectes danae in the Santa Cruz Channel, Brazil. Crabs of both sexes were measured at carapace width (CW), carapace length (CL), abdomen width (AW), length of the right chelipod (LRC), and dissected to visualize the gonads. The gonadal maturity was estimated based on the frequency of mature individuals per class of CW, and the determination of morphological maturity was based on the relationship between the structures LRC versus CW for males and AW versus CW for females. The sizes that 50% of females reached gonadal and morphological maturity were 62.5 and 59.5 mm CW respectively. In turn, the sizes that 50% of males reached gonadal and morphological maturity were 74.5 and 70.5 mm CW respectively. In the analysis of dispersion of points in relation to AW versus CW, it could be observed that juvenile females showed positive allometry and adult females showed negative allometry, indicating a higher growth rate during the juvenile phase, related to the need of expanding the abdomen for egg incubation at the adult phase. In the relation LRC versus CW, it was observed that both juvenile and adult males showed positive allometry, but changes in the degree of allometry were evident between the two phases. The exceeding growth of the chelipod of males may be related to the reproductive process, including courtship and agonistic interactions with other males.

The first finding of the alien crab Atergatis roseus (Xanthidae) in Rhodes Island (Hellenic south-eastern Aegean Sea) is documented, increasing to eleven the number of alien brachyurans present in the area, nine of them having Indo-Pacific origin. Due to its coloration, not in accordance with the literature, the specimen is described in detail.

The present paper provides the first record of the brachyuran crab species as by-catch from shrimp fishery practices in northern Rio de Janeiro State, south-eastern Brazil (21°30′S–21°50′S). Monthly samples were collected from April 2006 to March 2007 along the coastal fishing ground, from 0 to 4 nautical miles offshore and from 10 to 15 m depth. Eight species and 6833 crab specimens were recorded: Arenaeus cribarius (N = 11), Callinectes ornatus (N = 5613), Cronius rubber (N = 16), Hepatus pudibundus (N = 523), Libinia ferreirae (N = 202), Persephona mediterranea (N = 1), P. punctata (N = 466) and Portunus spinimanus (N = 1). A seasonal pattern of the crabs' occurrence was not found. The catches per unit effort values of C. ornatus were significantly greater than the other crabs and its high number indicates a resident pattern along the coastal fishing ground in the study area. The by-caught specimens of C. ornatus can be used as bait in Balistidae (triggerfish) fishery practice by the local fishermen, but the other crab species are discarded after by-catch.